O's to Q's, half P's to keys

O’s are ounces, and Q’s are quarter pounds. His deals are increasing 4x in size. Doubling again, he’s moving Half P(ound)s. Finally, in the largest deal of all, he sells “keys.” A key is a Kilogram of cocaine, about 2.2lbs.

He has and sells varying amounts of drugs. The leter P is also in between O and Q in the alphabet.